AU2009334831B2 - Odor controlled personal care compositions containing hydroxypropyl trialkylammonium salts - Google Patents

Abstract

A personal care composition is provided which includes from 0.1 to 30% of a dihydroxypropyltri(C-C alkyl) ammonium salt by weight of the composition; from 0.0001 to 0.005% of a tri(C-C alkyl) amine or protonated form thereof by weight of the ammonium salt; from 0.002 to 15% of an aluminum salt by weight of the composition; and a cosmetically acceptable carrier wherein the composition has a pH ranging from 5.5 to 6.9. Unpleasant amine odor from trialkyl amines which arise from the dihydroxypropyltri(C-C alkyl) ammonium salts is suppressed by the aluminum salt and by careful control of pH conditions.

Description

WO 2010/076293 PCT/EP2009/067923 ODOR CONTROLLED PERSONAL CARE COMPOSITIONS CONTAINING HYDROXYPROPYL TRIALKYLAMMONIUM SALTS BACKGROUND OF THE INVENTION 5 Field of the Invention The invention concerns control of odor arising from the presence of hydroxypropyl trialkylammonium salts in personal care compositions. The Related Art 10 Hydroxypropyl trialkylammonium salts have a number of beneficial cosmetic properties. Foremost is the ability of these salts to moisturize skin. The moisturization benefits have been revealed in US 7 087 560 B2 (McManus et al.), EP 1 807 041 B1 (Unilever), EP 1 804 922 B1 (Unilever) and US 7 282 471 B2 (Harichian et al.). 15 Another benefit of these salts is that they can mediate the signs of aging. This benefit is reported in US 7176172 B2 (Harding et al.). In developing dihydroxypropyl trialkylammonium salt containing personal care compositions, there has been noted a malodor problem. Off-odors have been attributed 20 to small amounts of low molecular weight trialkylamine continuously being generated from the salt compositions. Even small amounts of amine are readily detected by the human nose. US 2007/0299284 Al (Deavenport et al.) discloses attempts to inhibit malodors from 25 dihydroxypropyl trialkylammonium salts. Their solution is to reduce the pH of the intermediate reaction leading to the final quaternary ammonium salts. No guidance is provided on controlling odor of personal care compositions that may contain the salts. Accordingly, the present invention is focused upon reducing malodour arising from 30 volatile trialkylamine which is generated by dihydroxypropyl trialkylammonium salts in a formulated personal care composition.

WO 2010/076293 PCT/EP2009/067923 -2 SUMMARY OF THE INVENTION A personal care composition is provided which includes: (i) from 0.1 to 30% of a dihydroxypropyltri(C 1

-C

3 alkyl) ammonium salt by weight of the composition; 5 (ii) from 0.0001 to 0.005% of a tri(C 1

-C

3 alkyl) amine or protonated form thereof by weight of the dihydroxypropyltri (C 1

-C

3 alkyl) ammonium salt; (iii) from 0.002 to 15% of an aluminum salt by weight of the composition; and (iv) a cosmetically acceptable carrier, wherein the composition has a pH ranging from 5.5 to 6.9. 10 DETAILED DESCRIPTION OF THE INVENTION Now it has been found that aluminum salts can inhibit malodor formation resultant from decomposition of dihydroxypropyl tri(C 1

-C

3 alkyl) ammonium salts. It has further been found that generation of odor causing trialkylamines can be inhibited by formulating at a 15 pH ranging from 5.5 to 6.9, preferably from 6.0 to 6.8, and optimally from 6.2 to 6.8. Accordingly, a first element of the present invention is the dihydroxypropyl tri(C 1

-C

3 alkyl) ammonium salts. Ordinarily the C 1

-C

3 alkyl constituent of the quaternized ammonium group will be methyl, ethyl, n-propyl, isopropyl or hydroxyethyl and mixtures thereof. 20 Particularly preferred is a trimethyl ammonium group known through INC nomenclature as a "trimonium" group. Any anion can be used in the quaternary ammonium salts of this invention. The anion may be organic or inorganic with proviso that the material is cosmetically acceptable. Typical inorganic anions are halides, sulfates, phosphates, nitrates and borates. Most preferred are the halides, especially chloride. Organic anionic 25 counter ions include methosulfate, toluoyl sulfate, acetate, citrate, tartrate, glycolate, lactate, gluconate, and benzenesulfonate. Dihydroxypropyltri(C 1

-C

3 alkyl)ammonium salts may be obtained via a variety of synthetic procedures, most particularly by hydrolysis of chlorohydroxypropyltri(C 1

-C

3 30 alkyl)ammonium salts. A most preferred species is 2,3-dihydroxypropyltrimonium chloride, wherein the C 1

-C

3 alkyl is a methyl group.

WO 2010/076293 PCT/EP2009/067923 -3 Amounts of the dihydroxypropyl tri(C 1

-C

3 alkyl) ammonium salts may range from about 0.1 to about 30%, preferably from about 0.5 to about 20%, optimally from about 1% to about 12% by weight of the composition. 5 Trialkylamine arising from decomposition of the dihydroxypropyl tri (C 1

-C

3 alkyl) amine salts must be minimized. However, any steps to totally suppress amine by pH manipulation will adversely effect stability in the salts. For this reason, a small amount of tri(C 1

-C

3 alkyl) amine and/or protonated form thereof should be maintained within the compositions. These small amounts are insufficient to be aesthetically smelly but 10 sufficient to provide a balance against decomposition. Thus, the tri(C 1

-C

3 alkyl) amine and protonated form thereof in compositions of this invention ordinarily will be present in amounts from 0.0001 to 0.005, preferably from 0.0001 to 0.001, more preferably from 0.0001 to 0.0005, and optimally from 0.0001 to 0.0003% by weight of the dihydroxypropyltri (C 1

-C

3 alkyl) ammonium salts but insufficient in concentration to 15 exhibit a detectable odor (based on nose detection by 80% of a human sniff panel). A particular amine present in the compositions of this invention is trimethylamine and its protonated form trimethylamine hydrochloride. The protonated form of tri(C 1

-C

3 alkyl) amine is obtained from neutralization with a hydroacid such as hydrochloric. 20 Aluminum salts are a further component of compositions according to the present invention. A wide variety of aluminum bearing organic and inorganic substances are suitable for the present invention. Advantageously the aluminum salt is one easily dissociable in water. Preferably the aluminum salt has a solutility of at least 0.5 gram, especially at least 3 gram, and optimally at least 20 gram per 100 ml of water at 20 0 C. 25 Illustrative but not limiting examples of aluminum salts include aluminum chloride, aluminum acetate, aluminum bromide, aluminum nitrate, aluminum stearate, aluminum acetate, aluminum sulfate, aluminum Lakes, aluminum citrate, aluminum lactate and mixtures thereof. Amounts of the aluminum salt may range from about 0.002 to 15%, preferably from about 0.005 to about 1%, more preferably from about 0.01 to about 30 0.1%, and optimally from about 0.02 to 0.05% by weight of the composition. By the term personal care composition is meant any substance applied to a human body for improving appearance, cleansing, odor control or general aesthetics. Nonlimiting WO 2010/076293 PCT/EP2009/067923 -4 examples of personal care compositions include leave-on skin liquid products, shower gels, toilet bars, antiperspirants, deodorants, shave creams, depilatories, lipsticks, foundations, mascara, sunless tanners and sunscreen formulas. Personal care compositions of the present invention may be in any form. These forms may include 5 lotions, creams, roll-on formulations, sticks, mousses, aerosol and non-aerosol sprays and fabric (e.g. nonwoven textile)-applied formulations such as via adhesive patches or via wipes. Compositions of this invention may also include a cosmetically acceptable carrier. 10 Amounts of the carrier may range from about 1 to about 99.9%, preferably from about 70 to about 95%, optimally from about 80 to about 90% by weight of the composition. Among the useful carriers are water, emollients, fatty acids, fatty alcohols, thickeners and combinations thereof. The carrier may be aqueous, anhydrous or an emulsion. Preferably the compositions are aqueous, especially water and oil emulsions of the W/O 15 or O/W or triplex W/0/W variety. Water when present may be in amounts ranging from about 5 to about 95%, preferably from about 20 to about 70%, optimally from about 35 to about 60% by weight of the composition. Emollient materials may serve as cosmetically acceptable carriers. These may be in the 20 form of silicone oils, natural or synthetic esters and hydrocarbons. Amounts of the emollients may range anywhere from about 0.1 to about 95%, preferably between about 1 and about 50% by weight of the composition. Silicone oils may be divided into the volatile and non-volatile variety. The term "volatile" 25 as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic (cyclomethicone) or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. 30 Non-volatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially nonvolatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 x 10-6 to 0.1 m 2 /s at 25 0 C. Among the preferred non-volatile WO 2010/076293 PCT/EP2009/067923 -5 emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 1 x 10-5 to about 4 x 1 0 -4 m 2 /s at 251C. Another class of nonvolatile silicones are emulsifying and non-emulsifying silicone 5 elastomers. Representative of this category is DimethiconeNinyl Dimethicone Crosspolymer available as Dow Corning 9040, General Electric SFE 839, and Shin-Etsu KSG-18. Silicone waxes such as Silwax WS-L (Dimethicone Copolyol Laurate) may also be useful. 10 Among the ester emollients are: a) Alkyl esters of saturated fatty acids having 10 to 24 carbon atoms. Examples thereof include behenyl neopentanoate, isononyl isonanonoate, isopropyl myristate and octyl stearate. b) Ether-esters such as fatty acid esters of ethoxylated saturated fatty alcohols. 15 c) Polyhydric alcohol esters. Ethylene glycol mono- and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl mono-stearate, 20 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters. Particularly useful are pentaerythritol, trimethylolpropane and neopentyl glycol esters of C-C 30 alcohols. d) Wax esters such as beeswax, spermaceti wax and tribehenin wax. 25 e) Sugar ester of fatty acids such as sucrose polybehenate and sucrose polycottonseedate. Natural ester emollients principally are based upon mono-, di- and tri- glycerides. Representative glycerides include sunflower seed oil, cottonseed oil, borage oil, borage 30 seed oil, primrose oil, castor and hydrogenated castor oils, rice bran oil, soybean oil, olive oil, safflower oil, shea butter, jojoba oil and combinations thereof. Animal derived emollients are represented by lanolin oil and lanolin derivatives. Amounts of the natural esters may range from about 0.1 to about 20% by weight of the compositions.

WO 2010/076293 PCT/EP2009/067923 -6 Hydrocarbons which are suitable cosmetically acceptable carriers include petrolatum, mineral oil, C 11

-C

13 isoparaffins, polybutenes and especially isohexadecane, available commercially as Permethyl 101A from Presperse Inc. 5 Fatty acids having from 10 to 30 carbon atoms may also be suitable as cosmetically acceptable carriers. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, oleic, linoleic, linolenic, hydroxystearic and behenic acids. 10 Fatty alcohols having from 10 to 30 carbon atoms are another useful category of cosmetically acceptable carrier. Illustrative of this category are stearyl alcohol, lauryl alcohol, myristyl alcohol, oleyl alcohol and cetyl alcohol. Thickeners can be utilized as part of the cosmetically acceptable carrier of compositions 15 according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982@), hydrophobically-modified acrylates (e.g. Carbopol 1382@), polyacrylamides (e.g. Sepigel 305@), acryloylmethylpropane sulfonic acid/salt polymers and copolymers (e.g. Aristoflex HMB@ and AVC@), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, 20 hydroxypropyl methocellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Inorganics may also be utilized as thickeners, particularly clays such as bentonites and hectorites, fumed silicas, talc, calcium carbonate and silicates such as magnesium 25 aluminum silicate (Veegum@). Amounts of the thickener may range from 0.0001 to 10%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight of the composition. Humectants may be employed in the present invention. These are generally polyhydric alcohol-type materials. Typical polyhydric alcohols include glycerin, propylene glycol, 30 dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, isoprene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. The amount of WO 2010/076293 PCT/EP2009/067923 -7 humectant may range anywhere from 0.5 to 50%, preferably between 1 and 25%, and optimally from 10 to 20% by weight of the composition. Surfactants may also be present in compositions of the present invention. Total 5 concentration of the surfactant when present may range from about 0.1 to about 90%, preferably from about 1 to about 40%, optimally from about 0.1 to about 20% by weight of the composition, and being highly dependent upon the type of personal care product. The surfactant may be selected from the group consisting of anionic, nonionic, cationic and amphoteric actives. Particularly preferred nonionic surfactants are those with a C 1 0 10 C 20 fatty alcohol or acid hydrophobe condensed with from 2 to 100 moles of ethylene oxide or propylene oxide per mole of hydrophobe; C 2

-C

10 alkyl phenols condensed with from 2 to 20 moles of alkylene oxide; mono- and di-fatty acid esters of ethylene glycol; fatty acid monoglyceride; sorbitan, mono- and di- C 8

-C

20 fatty acids; and polyoxyethylene sorbitan as well as combinations thereof. Alkyl polyglycosides and saccharide fatty 15 amides (e.g. methyl gluconamides) and trialkylamine oxides are also suitable nonionic surfactants. Useful amphoteric surfactants include cocoamidopropyl betaine, C 12

-C

2 0 trialkyl betaines, sodium lauroamphoacetate, and sodium laurodiamphoacetate. 20 Preferred anionic surfactants include soap, alkyl ether sulfates and sulfonates, alkyl sulfates and sulfonates, alkylbenzene sulfonates, alkyl and dialkyl sulfosuccinates, C 8

-C

2 0 acyl isethionates, C 8

-C

20 alkyl ether phosphates, C 8

-C

2 0 sarcosinates, C 8

-C

20 acyl lactylates, sulfoacetates and combinations thereof. 25 Sunscreen agents may also be included in compositions of the present invention. Particularly preferred are such materials as ethylhexyl p-methoxycinnamate, available as Parsol MCX@, Avobenzene, available as Parsol 1789@ and benzophenone-3, also known as Oxybenzone. Inorganic sunscreen actives may be employed such as microfine (e.g. 30 from 0.1 to 200 micron average size) titanium dioxide and zinc oxide. Amounts of the sunscreen agents when present may generally range from 0.1 to 30%, preferably from 2 to 20%, optimally from 4 to 10% by weight of the composition.

WO 2010/076293 PCT/EP2009/067923 Preservatives can desirably be incorporated into the personal care compositions of this invention to protect against the growth of potentially harmful microorganisms. Particularly preferred preservatives are phenoxyethanol, methyl paraben, propyl paraben, imidazolidinyl urea, dimethyloldimethylhydantoin, ethylenediaminetetraacetic acid salts 5 (EDTA), sodium dehydroacetate, methylchloroisothiazolinone, methylisothiazolinone, iodopropynlbutylcarbamate and benzyl alcohol. The preservatives should be selected having regard for the use of the composition and possible incompatibilities between the preservatives and other ingredients. Preservatives are preferably employed in amounts ranging from 0.0001% to 2% by weight of the composition. 10 Compositions of the present invention may include vitamins. Illustrative vitamins are Vitamin A (retinol), Vitamin B 2 , Vitamin B 3 (niacinamide), Vitamin B 6 , Vitamin C, Vitamin E, Folic Acid and Biotin. Derivatives of the vitamins may also be employed. For instance, Vitamin C derivatives include ascorbyl tetraisopalmitate, magnesium ascorbyl phosphate 15 and ascorbyl glycoside. Derivatives of Vitamin E include tocopheryl acetate, tocopheryl palmitate and tocopheryl linoleate. DL-panthenol and derivatives may also be employed. Total amount of vitamins when present in compositions according to the present invention may range from 0.001 to 10%, preferably from 0.01% to 1%, optimally from 0.1 to 0.5% by weight of the composition. 20 Another type of useful substance can be that of an enzyme such as elastases, amylases, oxidases, proteases, lipases and combinations. Skin lightening compounds may be included in the compositions of the invention. Illustrative substances are placental extract, lactic acid, niacinamide, arbutin, kojic acid, 25 ferulic acid, resorcinol and derivatives including 4-substituted resorcinols and combinations thereof. Amounts of these agents may range from about 0.1 to about 10%, preferably from about 0.5 to about 2% by weight of the composition. Desquamation promoters may be present. Illustrative are the alpha-hydroxycarboxylic 30 acids and beta-hydroxycarboxylic acids. The term "acid" is meant to include not only the free acid but also salts and C-C 30 alkyl or aryl esters thereof and lactones generated from removal of water to form cyclic or linear lactone structures. Representative acids are glycolic, lactic and malic acids. Salicylic acid is representative of the beta- WO 2010/076293 PCT/EP2009/067923 -9 hydroxycarboxylic acids. Amounts of these materials when present may range from about 0.01 to about 15% by weight of the composition. A variety of herbal extracts may optionally be included in compositions of this invention. 5 The extracts may either be water soluble or water-insoluble carried in a solvent which respectively is hydrophilic or hydrophobic. Water and ethanol are the preferred extract solvents. Illustrative extracts include those from green tea, chamomile, licorice, cinnamonum ilicioides, aloe vera, grape seed, citrus unshui, willowbark, sage, thyme and rosemary. 10 Also included may be such materials as lipoic acid, retinoxytrimethylsilane (available from Clariant Corp. under the Silcare 1M-75 trademark), dehydroepiandrosterone (DHEA), flavanoids and combinations thereof. Ceramides (including Ceramide 1, Ceramide 3, Ceramide 3B and Ceramide 6) as well as pseudoceramides may also be useful. Amounts 15 of these materials may range from about 0.000001 to about 10%, preferably from about 0.0001 to about 1% by weight of the composition. Colorants, opacifiers and abrasives may also be included in compositions of the present invention. Each of these substances may range from about 0.05 to about 5%, preferably 20 between 0.1 and 3% by weight of the composition. A wide variety of packaging can be employed to store and deliver the personal care compositions. Packaging is often dependent upon the type of personal care end-use. For instance, leave-on skin lotions and creams and shower gels generally employ plastic 25 containers with an opening at a dispensing end covered by a closure. Typical closures are screw-caps, non-aerosol pumps and flip-top hinged lids. Packaging for antiperspirants, deodorants and depilatories may involve a container with a roll-on ball on a dispensing end. Alternatively these types of personal care products may be delivered in a stick composition formulation in a container with propel-repel mechanism where the stick 30 moves on a platform towards a dispensing orifice. Metallic cans pressurized by a propellant and having a spray nozzle serve as packaging for antiperspirants, shave creams and other personal care products. Toilette bars may have packaging constituted by a cellulosic or plastic wrapper or within a cardboard box or even encompassed by a WO 2010/076293 PCT/EP2009/067923 -10 shrink wrap plastic film. All of the aforementioned are considered packaging within the context of the present invention. The term "comprising" is meant not to be limiting to any subsequently stated elements 5 but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. 10 Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word "about". All documents referred to herein, including all patents, patent applications, and printed 15 publications, are hereby incorporated by reference in their entirety in this disclosure. The following examples will more fully illustrate the embodiments of this invention. All parts, percentages and proportions referred to herein and in the appended claims are by weight unless otherwise illustrated. 20 EXAMPLE 1 A lotion illustrative of the present invention is outlined in table I below. This formula incorporates a 2,3-dihydroxypropyl trimethylammonium chloride salt and a citric acid/sodium citrate buffer to achieve a pH of 5.5. A small amount of trimethylamine is 25 present. TABLE I INGREDIENT* WEIGHT % PHASE A Water Balance Disodium EDTA 0.05 Methyl Paraben 0.15 Aluminum Chloride 0.60 Triethanolamine 1.20 2,3-Dihydroxypropyl trimethylammonium 1.00 WO 2010/076293 PCT/EP2009/067923 - 11 Chloride -Citric Acid/Sodium Citrate * PHASE B Xanthan Gum 0.20 Butylene Glycol 3.00 Glycerin 2.00 PHASE C Sodium Stearoyl Lactylate 0.10 Glycerol Monostearate 1.50 Stearyl Alcohol 1.50 Isostearyl Palmitate 3.00 Silicone Fluid 1.00 Cholesterol 0.25 Sorbitan Stearate 1.00 Butylated Hydroxy Toluene 0.05 Vitamin E Acetate 0.01 PEG-100 Stearate 2.00 Stearic Acid 3.00 Propyl Paraben 0.10 Parsol MCX@ 2.00 Caprylic/Capric Triglyceride 0.50 Hydroxycaprylic Acid 0.01 C12-15 Alkyl Octanoate 3.00 PHASE D Vitamin A Palmitate 0.10 Bisabolol 0.01 Vitamin A Acetate 0.01 Fragrance 0.03 Retinol 50C 0.02 Conjugated Linoleic Acid 0.50 * 0.00005% trimethylamine present. ** Amount sufficient to achieve pH 5.5. EXAMPLE 2 5 A shampoo composition useful in the context of the present invention is described in table Il below. TABLE || Ingredient* Weight % Ammonium Laureth Sulfate 12.00 Ammonium Lauryl Sulfate 2.00 Cocoamidopropyl Betaine 2.00 Sodium Lauroamphoacetate 2.00 Glycerin 12.00 2,3-Dihydroxypropyl 5.50 WO 2010/076293 PCT/EP2009/067923 - 12 Ethyldimethylammonium Sulfate Ethylene Glycol Distearate 1.50 Cocomonoethanolamide 0.80 Cetyl Alcohol 0.60 Polyquaternium-10 0.50 Dimethicone 1.00 Zinc Pyridinethione 1.00 Citric Acid 0.39 Sodium Xylene Sulfonate 1.00 Fragrance 0.40 Aluminum Acetate 0.25 Kathon CG@ 0.0008 Benzyl Alcohol 0.0225 Citric Acid/Sodium Citrate ** Water Balance * 0.00001% ethyl dimethylamine present ** Amount of citric acid/sodium citrate sufficient to achieve pH 6.2. EXAMPLE 3 5 Experiments were conducted to evaluate the effect of various metal ions to improve stability of 2,3-dihydroxypropyl trimethylammonium chloride (hereinafter "DPAC") in controlling decomposition into trimethylammonium hydrochloride (hereinafter TMA.HCI). Samples for these experiments utilized DPAC at 50% w/w in an aqueous system with different specified metal ion sources. The samples were prepared by either of the 10 following two methods: (1) Non-buffered condition: a mixture of DPAC and metal ion salt were titrated by either hydrochloric acid or sodium hydroxide to achieve a pH around 6.2; or (2) Buffered condition: wherein DPAC and the metal ion salt were mixed with 0.1 M phosphate buffer of pH 6.2. Mixtures of the DPAC and metal ion salt were stored at different temperature conditions and the TMA.HCI level was monitored at specified 15 storage time intervals. Method for TMA headspace measurement for DPAC stored at different temperatures and with metal ions Buffer solution: 0.5M of phosphate buffer with pH 12 is prepared. 20 WO 2010/076293 PCT/EP2009/067923 -13 Sample preparation for GC analysis: 1.8ml of pH 12 phosphate buffer (0.5M) and 0.2ml of DPAC sample (containing TMA.HCL) are pipetted into in a 20ml GC headspace sampling vial. The GC sampling vial is then sealed with caps with septum, both from Gerstel, Inc. 5 Instrument: Solid phase microextraction (SPME) - gas chromatography (GC) 6890 / mass spectrometry (MS) 5973/ flame ionization detector (FID) was used for TMA quantification. The GC column is a HP-5MS column from Agilent (inner diameter 0.25mm, length 30m, stationary phase thickness 0.25um). 10 GC conditions: Injector in splitless mode with helium gas as carrier gas. Injection port is heated to 250 oC, purge flow to split vent 50ml/min at 2 minutes. Column is in constant flow mode with 1.3 ml/min flow rate. Oven temperature ramp: hold at 45 oC for 2 minutes, then increase oven temperature at a rate of 3 oC/min to 50 oC, 15 oC/min to 280 oC and hold for 2 minutes. MS conditions are: solvent delay for 0.2 minutes, scan 15 starting from low mass 30 to high mass 300. Autosampler's conditions are: SPME fiber, 2cm-50/30um DVB/Carboxen/PDMS stableFlex for manual or auto holder notched gray. Supelco 57348-U, was used. The GC vial was incubated at 55oC for 15 min without agitation. Extraction time is 5 min and the fiber 20 was then desorb in GC injector for 15 min. Data analysis for TMA quantification: Manual integration of the 59.1 ion around 2.2 to 2.5 minute (retention time) was performed to get the peak area of TMA for the samples and for the calibration samples. A calibration curve of TMA peak area vs. TMA.HCI 25 concentration in water (as ppm) will be constructed. The TMA.HCI amount in the samples are thus calculated against the calibration curves. Metal salts was also added into 10ppm TMA.HCI water solution at the same level tested in sample, to check whether the calibration curve might shift (which did not at the presence of all the metal ions that tested). 30 WO 2010/076293 PCT/EP2009/067923 - 14 In the first set of experiments, aluminum chloride was evaluated under a buffered pH of 6.2. The aluminum ion at 0.025% (250 ppm) level was found to suppress the formation of TMA.HCI, especially at storage temperatures higher than ambient. See table Ill. 5 TABLE Ill Storage Temperature, 0 C* 2 week Ambient 40 0 C 50 0 C Control (DPAC) 1.61 2.8 3.73 Aluminum Chloride and DPAC 1.9 1.8 1.7 4 week Control (DPAC) 2 4.84 7.01 Aluminum Chloride and DPAC 2.63 2.55 3.03 12 week Control (DPAC) 4.62 -- 13.19 Aluminum Chloride and DPAC 3.19 -- 5.14 * Numbers reported in this table are for TMA.HCI multiplied by 1 0 4 weight % with experimental error of +/- 0.3 x 1 0 4 weight %. Experiments were also conducted to determine the effect of aluminum potassium sulfate 10 under a buffered pH of 6.2. Level of aluminum ion was 0.025% (250 ppm). Once again, it is evident from table IV that aluminum ions can slow the TMA.HCI formation, especially at storage temperatures higher than ambient. TABLE IV Storage Temperature, OC* 2 week Ambient 50 0 C Control (DPAC) 4.42 11.45 Aluminum Potassium Sulfate and 3.77 3.58 DPAC 4 week Control (DPAC) 5.06 14.34 Aluminum Potassium Sulfate and 3.88 3.64 DPAC 15 * Numbers reported in this table are for TMA.HCI multiplied by 10 4 weight % with experimental error of +/- 0.3 x 1 0 4 weight %. Effect of aluminum silicate was also evaluated at 0.025% (250 ppm) level of aluminum ion. The employed media was un-buffered with the pH being set at approximately 6.2.

WO 2010/076293 PCT/EP2009/067923 - 15 Again it is seen that aluminum ion, this time from aluminum silicate slows down the TMA.HCI formation from a DPAC containing medium. TABLE V Storage Temperature, 0 C* 2 week Ambient 50 0 C Control (DPAC) 3.22 5.18 Aluminum Silicate and DPAC 3.56 3.93 5 * Numbers reported in this table are for TMA.HCI multiplied by 1 0 4 weight % with experimental error of +/- 0.3 x 1 0 4 weight %. Still further experiments were conducted to determine the effect of other metal ions. Magnesium ion was evaluated at 0.005% (50 ppm) generated from magnesium sulfate. 10 Calcium ion was evaluated at a level of 0.025% (250 ppm) generated from calcium chloride. Evaluations were performed in an un-buffered system where pH was 6.2 throughout storage. Results are recorded in table VI as to their effect upon formation of TMA.HCI. It was found that within experimental error (+/- 0.3 x 10 4 weight %), the level of TMA.HCI was not be effected by the presence of calcium or magnesium ions. 15 TABLE VI Storage Temperature, OC* 2 week Ambient 40 0 C 50 0 C Control (DPAC) 3.05 3.28 3.69 Calcium Chloride and DPAC 2.52 3.19 3.26 Magnesium Sulfate and DPAC 2.95 3.19 3.80 4 week Control (DPAC) 2.82 3.74 4.88 Calcium Chloride and DPAC 2.79 3.88 4.64 Magnesium Sulfate and DPAC 2.76 3.83 4.29 8 week Control (DPAC) 3.17 -- 5.93 Calcium Chloride and DPAC 2.77 -- 5.38 Magnesium Sulfate and DPAC 3.20 -- 5.53 * Numbers reported in this table are for TMA.HCI multiplied by 1 0 4 weight % with experimental error of +/- 0.3 x 1 0 4 weight %. 20 Levels of ferric ion at 0.005 weight % (50 ppm) were evaluated for their effect on TMA.HCI formation during DPAC storage. The system was buffered to 6.2. Results are C:WRPonbI\DCC\TZM430572_1 DOC-2/05/20 12 - 16 found in table VII. In these experiments it is seen that ferric ion had a negative effect in controlling TMA.HCI formation. TABLE VII Storage Temperature, *C* 2 week Ambient 40 0 C 50 0 C Control (DPAC) 1.61 2.80 3.73 Ferric Chloride and DPAC 4.52 5.38 4.94 4 week Control (DPAC) 2.00 4.84 7.01 Ferric Chloride and DPAC 5.52 7.37 9.61 8 week Control (DPAC) 4.62 -- 13.19 Ferric Chloride and DPAC 6.60 -- 19.47 * Numbers reported in this table are for TMA.HCI multiplied by 10 ' weight % with experimental error of +/- 0.3 x 10- weight %. A set of experiments were also done to evaluate the effect of aluminum chloride 0.0250 weight % (250 ppm) on formation of TMA.HCI at an un-buffered pH of 3.8. Table VIII below reports observations. At low pH such as 3.8, the rate of formation of TMA.HCI is greater than in the absence thereof. TABLE VIII Storage Temperature, OC* 2 week Ambient 40 0 C 50 0 C Control (DPAC) 3.99 4.16 4.67 Aluminum Chloride and DPAC 4.60 5.64 6.78 * Numbers reported in this table are for TMA.HCI multiplied by 10 weight % with experimental error of +/- 0.3 x 10' weight %. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be 5 understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or 10 admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims (10)

1. A personal care composition comprising: (i) from 0.1 to 30% of a dihydroxypropyltri(C-C 3 alkyl) ammonium salt by weight of the composition; (ii) from 0.0001 to 0.005% of a tri(C-C 3 alkyl) amine or protonated form thereof by weight of the dihydroxypropyltri (C 1 -C 3 alkyl) ammonium salt; (iii) from 0.002 to 15% of an aluminum salt by weight of the composition; and (iv) a cosmetically acceptable carrier, wherein the composition has a pH ranging from 5.5 to 6.9.

2. A composition according to claim 1 wherein the ammonium salt is dihydroxypropyl trimethylammonium salt.

3. A composition according to claim 1 or claim 2 wherein the tri (C-C 3 alkyl) amine or protonated form thereof is present in an amount from 0.0001 to 0.001% by weight of the dihydroxypropyltri (C-C 3 alkyl) ammonium salt.

4. A composition according to any one of the preceding claims wherein the aluminum salt is selected from the group consisting of aluminum chloride, aluminum acetate, aluminum bromide, aluminum nitrate, aluminum stearate, aluminum acetate, aluminum sulfate, aluminum Lakes, aluminum citrate, aluminum lactate and mixtures thereof.

5. A composition according to any one of the preceding claims wherein the aluminum salt is present in an amount from 0.02 to 0.05% by weight of the composition.

6. A composition according to any one of the preceding claims wherein the amine is trimethylamine.

7. A composition according to any one of the preceding claims wherein the pH ranges from 6.0 to 6.8. C :\RPorbI\DCCTZM\43tX)572.1 DOC.25/2012 - 18

8. A composition according to any one of the preceding claims further comprising a surfactant present in an amount from 0.1 to 20% by weight of the composition.

9. A composition according to any one of the preceding claims further comprising glycerin in an amount from 10 to 20% by weight of the composition.

10. A composition according to claim 1, substantially as hereinbefore described with reference to the Examples.